In Christianity, the Holy Spirit (sometimes referred to as the Holy Ghost) is the third person in the Trinity, co-equal with God the Father and God the Son in the Godhead. Within the Christian denominations, there is a diversity in thought as to the nature of the Holy Spirit.
Regular Websites
Foundation for the Holy Spirit
The focus of the Foundation is on providing resources, teaching and counseling to help people to rely more upon the Holy Bible and the words of the Holy Spirit. - Foundation for the Holy Spirit
http://www.forholyspirit.org/
With a focus on the Holy Spirit, the topics found here include the Holy Spirit and the Bible, a Bible study series on the Holy Spirit, baptism in the Holy Spirit, and a free spiritual gifts profile. - The Holy Spirit
http://www.theholyspirit.com/
Features an entry from an online encyclopedia of biblical Christianity with information on the personhood, deity and roles of the Holy Spirit, as well as the various titles that apply to the Spirit. - Theopedia: Holy Spirit
http://www.theopedia.com/Holy_Spirit